The automotive industry is continually striving to attain reductions in engine fuel consumption and among the various systems and devices proposed heretofore by the prior art is the use of a duty-cycle type of electromagnetic fuel metering valving assembly. Generally, as is well known in the art, such duty-cycle valving assemblies employ a generally cyclically energized field coil which causes an associated armature-positioned valving member to open and close against a cooperating valve seating surface to intermittently permit and cease fuel flow to the engine. Generally, the average amount of time, within a given span of time, that the valve member is opened will determine the then metered rate of fuel flow to the engine.
In such duty-cycle valving assemblies an important requirement is that the valving assembly deliver the precise rate of metered fuel flow then required by the engine. In this area, the prior art has had difficulty, to say the least, in obtaining a valving member which when seated operated to fully and assuredly terminate fuel flow therepast. Often, the valve member selected comprises a generally spherical valving surface intended to seat against a cooperating valve seating surface. Since the various elements comprising such duty-cycle injector or valving assemblies are manufactured separately, the inter-related concentricities thereof become an important factor in ultimately determining whether required valve seating and fuel flow sealing characteristics are obtainable. The duty-cycle injector or valving assemblies heretofore proposed by the prior art and which have found acceptance, in terms of performance, require very precise and expensive machining processes in order to attempt to attain the required concentricities of, for example, the armature-positioned valve member and valve seat means.
The invention as herein disclosed and described is primarily directed to the solution of the aforestated problems of the prior art and to provide structure which is comparatively inexpensive to produce and yet provide the required seating of the valving member and the attendant required termination of fuel flow therepast.